Just trying to save you a reg fee, but good luck in the wild frontier of .org.uk. One thing they do have going for them is that they seem to get higher Google placement in the natural listings, as Google seems to prefer to promote non commercial people naturally, leaving the commercial ones to pay for adwords. Check keywords like catalogue on Google.
Just as an FYI:
org.uk Second Level Domain
The org.uk Second Level Domain is managed by Nominet UK and is a fully open domain. It is for organisations which do not 'fit' into any of the other Second Level Domains of the .uk Top Level Domain. These may include: charities, trades unions, political parties, community groups, educational councils, professional institutions, etc.
co.uk Second Level Domain
The .co.uk domain is managed by Nominet UK and is a fully open domain. It is intended for use by commercial enterprises and businesses, and is the largest Second Level Domain in the UK.